The femoral-neck plate of the previously known femoral-neck implant has a mostly U-shaped cross section. The outside of the web of the U-profile forms the outer contact surface onto the femur. In one piece with the upper end of the femoral-neck plate is the shaft, which in the known femoral-neck implant is called a blade. The blade has a U- or I-shaped cross section.
For the known femoral-neck implant the implantation process is as follows: in the case of a pertrochantery or a fracture of the femoral neck, an acceptance channel is produced manually below the trochanter with a mortising instrument adapted to the cross-sectional shape of the blade, and of suitable axial length, e.g. only into the neck of the femur, or if required into the head of the fumur. Thereafter the blade is slid into this receiving channel of bone, whereupon the femoral-neck plate is fastened exteriorily to the femur with corticalis screws.
Firstly, this known implant is unsatisfactory because the formation of the receiving channel for the blade requires much labor and time. Furthermore, during the creation of the channel, faulty angular orientation, displacement of axes, and further splintering of bones can occur.
However, the main disadvantage of the known femoral-neck implant resides in the fact that its application to unstable pertrochantery fractures, such as type Evans III and IV is indeed possible with great operative effort, but an immediate or primary postoperative load application while retaining the physiological angle of the femoral neck is impossible.
By contrast, primary postoperative loading tends to cause a mechanical collapse of the osteosynthesis previously undertaken. Since mostly elderly people who suffer unstable pertrochantery fractures must not get up for several days after the operation upon the application of the previously known implant, there exists for these patients an increased danger of complications cause by immobility, for example in form of pneumonia.